In manufacturing heat-shrinkable hoses or pipes of thermoplastic material, it is known generally to continuously extrude the hose, which is then cross-linked and, finally, continuously or discontinuously expanded.
It is also known to manufacture heat-shrinkable hoses of a fabric of threads, wherein a thread extending circumferentially around the hose has heat-shrinking properties, as disclosed by U.S. Pat. No. 3,669,157. Threads extending longitudinally along the axis of the hose are non-shrinkable. The threaded fabric is sealed by saturating the hose with curable substances. This method is relatively time-consuming and expensive.